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Research Projects

Sub/intra-cortical microstimulation is essential for delivering sensory feedback in neural prosthetic applications. However, it has been shown that micro-stimulation evokes wide spread downstream neuronal activation, losing its specificity. We are developing different stimulation strategies to shape downstream neural activity, with the goal being to increase the specificity of micro-stimulation.

We are interested in neural basis of the sense of touch, especially how information related to touch is encoded in various brain structures within the somatosensory pathway of the brain. External stimuli cause mechnoreceptors embedded in the skin to fire discrete electrical impulses (spikes, or action potentials). These spikes then propogate to the primary somatosensory cortex through various stages within this pathway, ultimately forming the substrate for tactile sensations. How the features of tactile stimuli are represented in the thalamus and cortex (neural coding)? On the other hand, from the prospective of the brain, what the brain sees is the distributed spike trains. How does the brain extract information about external stimuli from spike trains (reading a neural code or neural decoding)?

The sense of touch is crucial for humans to explore and manipulate the external world. For instance, when an individual touches an object, forces are imposed on the skin, causing a complicated pattern of skin deformation. The deformation as well as the posture and motion of various limb segments are conveyed to the brain, forming the perception of the properties of the object, such as shape and stiffness. We have developed a high performance, portable tatile stimulator array to probe sensory processing in the brain. Using the tactile stimulator array, we have discovered complex interplay between tactile and visual processing (see Report by MIT Tech Talk (pg. 5)). We are also using the device, in concert with non-invasive neuroimaging techniques, to probe abnormal perceptual processing in diseased brain.